In recent conferences or lectures, presentation is done not by printing presentation materials created by a personal computer (to be referred to as a PC hereinafter) but by enlarging and projecting the contents of the display screen of the PC by using, e.g. a video projector.
Generally, to enlarge and project the output video signal of a PC by a video projector, the PC and video projector must be connected by a cable to transmit the output video of the PC. However, if a video projector is shared by a plurality of PCs, it is cumbersome to connect the PCs and video projector by a cable in every setting. There is room for further improvement of usability. For this reason, wireless video transmission apparatuses for transmitting a video signal by wireless LAN without connecting a PC and a video projector by a cable are available on the market.
Such wireless video transmission apparatuses with the wireless LAN function include known apparatuses having a function of divisionally enlarging and projecting, on a projection screen, video signals on the display screens of a plurality of PCs or a function of transmitting the video signal on the display screen of a PC to a plurality of wireless video transmission apparatuses.
There is an infrastructure called a multimonitor which outputs a signal from one PC to a plurality of monitors. In the multi-monitor, a plurality of video cards are added to the PC, and two or more displays are displayed as if they were one large screen.
However, when one PC and a plurality of wireless video transmission apparatuses are wirelessly connected, the following problems are posed.
1. Since projection performance such as the resolution changes between the wireless video transmission apparatuses, it is cumbersome to select and use one wireless video transmission apparatus.
2. Since a plurality of wireless communication protocols are installed on the wireless video transmission apparatus side, it is cumbersome to select and use one wireless video transmission apparatus.
3. Since a plurality of video cards and hardware resources are necessary, the devices are expensive. For these reasons, the convenience to users is considerably poor in implementing multimonitor presentation using the conventional external apparatuses so no excellent usability is obtained.
It is an object of the present invention to save time and eliminate trouble for a user in selecting, as a data transmission destination, one of a plurality of external apparatuses such as wireless video transmission apparatuses.